Magneto



P 1927' c. H. TOWER MAGNETO Filed June 19, 1920 3 Sheets-Sheet 1 Sept. 20, 1927- c. H. TOWER MAGNETO Filed June 19, 1920 3 Sheets-Sheet 2 WW I:

Sept. 20, 1927.

C H. TOWER MAGNETO Y Y Filed June 19. 1920 5 Sheets-Sheet 3 Patented Sept. 20, 1927.

UNITED STATES PATENT OFFICE.

CHARLES H. TOWER, OF CLEVELAND, OHIO. ASSIGNOR, BY MESNE ASSIGNMENTS, TO SPLITDORF-BETHLEHEM ELECTRICAL COMPANY, OF NEWARK, NEW JERSEY, A.

CORPORATION OF NEW JERSEY.

MAGNETO.

Application filed June 19,

The invention relates to i ition generators and is especially applica le to magneto generators of the inductor type, although the improvements are by no means limlted to that type of generators.

The invention has for'its principal objects: (a) the reduction of the cost of producing ignition generators, (b) the reduction of the size and Weight of such generators, (0) the increase of the efiiclency f ignition generators, and (d) a. COIl StI'11Ct1OIl permitting easy assembly and disassembly of the parts.

Other objects, moreor less ancillar to the above, as well as the manner in w 1ch all of the objects are attained, will be pointed out in the following discussion and accompanying drawings.

In the drawings, Fig. 1 is a. central vertical section through an inductor type, hlgh tension generator embodying my improvements.

Fig. 2 is a section on the line 2-2, Fig. 1.

Fig. 3 is a. right end elevation of the generator, 'part 0 the breaker casing being broken away. I

Fig. 4 is a section on the line 4-4, Fig. 1.

Fig. 5 is a section on the line 5-5, Fig. 1.

Fig. 6 is a section on the line 6 6, Fig. 2.

Referring in detail to the construction illustrated, (1) indicates in its entirety astator frame structure integrally cast of nonmagnetic metal. This frame may be cast in any suitable manner and of any suitable non-magnetic metal, but I prefer to die-cast it and to use a suitable aluminum alloy to reduce the wei htof the structure as much as possible. e frame (1) com rises a. base part (1), end walls (1) and 1) and side walls (1) and (1).

In th base part of the frame (1) iron pole piece (2) formed with a po ar sur-. face (2). The pole piece (2) serves also as a portion of the base of the generator, being preferably formedwith tapped holes (2") to receive hold down screws. In the upper part of frame (1) are arranged a main pole piece (3) having a I second pole piece..(4 having a polar face isan (4). The pole pieces (2), (3) and (4) are embedded and secured in the integral frame (1) and made'a unitary part thereof by being placed in the die or mold when the frame is cast the parts' being formed so that lar face (3") and a 1920. Serial No. 300,207.

the pole pieces and the inte al frame structure have a secure interloc ing engagement after the metal of the frame has solidified. I

The pole piece (3) comprises a lower part (3'), which is partially embedded in the non-magnetic metal, and an upwardly extending core part (3). The pole piece (4) preferably is partially embedded throughout its length in the wall (1") of the non-magnetic frame. I

The bottom pole peice (2 is preferably made of cast iron but I pre or to'make the pole pieces (3) and (4) of laminated soft iron. The core extension (3 piece (3) is preferabl turne L cylindrical form as in icated in 5.

The high tension generating winding (5).

of the pole is removablymounted on the core extension tween the magnetic member (6) and the core (3) and the pole. iece (4), its, object being to increase the e ective area of contact between these parts and the area of the iron path between the ma ets and the .pole piece (4). As shown the plate (7) Y is formed with an aperture to fit over the end of the core (3).

(8, 8) are L-shaped permanent magnets having their upper ends engaging the top of the magnetic member (6) and their lower ends engaging the side of the bottom pole piece (2), the engagement between the-magnets and said parts (6) and (2) being on plane surfaces at right angles to each other.

A sheet metal cover plate (9) .is secured tothe base of the stator structure by screws down to the section (5) and a sec- (1G, 10) and serves to hold the memberf'w) and ma net 8) in o eratiye ition The si tator struct-uI e is forih d' or bored out to receive an inductor rotor designatedin its entirety by the numeral $11). Said rotor comprises the shaft" (12 p and "the? laminated flux distributing section (13.).

mounted thereon. The shaft has its drive end mounted in anv anti-friction bearing (14) in the end wall (1) of the stator frame whileits other end is mounted in a similar bearing (15) in a removable end plate (16) of the stator frame, said end plate being,

I shown it comprises a tubular shaft r is connected at its inner end to a stem on which the gear (23) is mounted, and a rotating member (26) fitted in the shaft (25) and caused to rotate therewith by the stud (27) which, as shown, is formed integral with one of the rivets which secure the gear (23) to the shaft (25) A hearing bushing (28) is preferably provided-for the shaft (25). A radially extending metal arm 3 which in turn is electrically connected through spring pressed brushes (31) and (32), to the high tension terminal (33) of the generating winding (5). The brush (32) is mounted as shown in a. block (34) of suitable insulating material said block bein secured by screws (not shown) to the end plate (1) of the stator frame.

The radially extending conductor (29), in operation, successively engages spring pressed terminal brushes (35) mounted in the usual manner in the removable distributorcover (36). Spring clips (37, 37) serve to secure the distributor cover in place. The die-cast stator frame is formed with a chamber (38) which serves to house a safety spark gap (39), said spark ap comprising an electrode (39) electrical y connected to the high tension terminal of the winding (5) and an electrode (39") adjustably mounted in the said wall (1) of the stator frame.

(40) is a condenser which is conveniently mounted on the said wall (1) of the said frame.

The primary and secondary sections of the generating winding, the condenser and the circuit breaker are connected in the usual manner which is well understood and which I have therefore not illustrated.

In the manufacture of my improved generator, the bottom pole-piece (2) is cast as nearly as may be to the final form, and the laminae for'the ,pole pieces (3) and (4) ,p are stamped out approximately to the form shown in "Fig. 2 and are then riveted toether as indicated. After the pole piece l3) has been riveted it is placed in a lathe trode (39 is inserted and the generating coil (5) as a iinit is slipped over the upper end of the core (3) with its high tension terminal(33)engaging the brush (32). and its spark'gap electrode (39). opposite the electrode (39). Then the magnetic member (7) (if used) is placed in position over the upper end of the core (3?), the magnetic member. (6), suitably machined, is placed in position, the condenser (40) is secured in position, and the permanent magnets are applied as shown in Fig. 2. The cover part (9) is then put on and secured by screws (10) thus e'fiectively securing the parts (6) and (7) and the magnets (8) in position. It will be observed that the bottom pole structure consists essentially of the pole piece (2),jwhile the upper pole structure includes the pole piece (3) and the core (3) the pole piece 4), the magnetic member, (6) and the part if the latter is used.

The manner of assembling the rotor, breaker and distributor parts and of making the electrical connections will be understood .fnom the foregoing. description.

In the operation of the generator, with the rotor turning in the direction indicated by the arrow in Fig. 2, it will be seen that the .flux distributor (1 3) causes the flux of the magnets to pass first through the core (3) and its surrounding generating winding (5) and then through the pole piece (4) and "outside of the generating winding, the pole piece (4) constituting a magnetic by-pass for the flux.

generating winding is opened approximately when the decrease of flux through the core (3) is at its maximum, with the consequent are more easily bent to form and more readily machined and fitted tot-he frame than are U-shaped magnets, for example. 'Thus The breaker mechanism is timed so that the primary circuit of the in grinding the sides of the magnets at their ends where they engage the top pole structure and the bottom pole piece it is only necessary that the surfaces be ground at right angles to each other, Whereas in the case of U-shaped magnets it is necessary that the surfaces be ground parallel to each other and also to given dimensions. This feature of my invention reducesthe cost of production. a

Again, by forming the top pple pieces (3) and (4:) separately, it is possi le to turn the core extension (3 to cylindrical form,

small in proportion to its capacity because the L-shaped magnets make it possible to reduce the height of the machine in comparison with prior forms of inductor generators using straight magnets; and this reduction of sizeis further made possible b the use of the round generating coil whic is more.

eificient than coils ofre'ctangular form. The higher efiiciency of the round generating coil arises from the fact that for a given flux path area the circular winding gives the shortest mean length of turn for the windingwith a. consequent minimum resistance, and from the further fact that at low generator speeds the heat of the spark or the length of gap the spark will jump varies inversely as the resistance of the primary winding, other conditions remaining unchanged. Furthermore, by length of the. mean turn of the winding low a smaller winding conductor can be used without exceeding a given resistance, so that the mean distance of the coil'turns from the core and, consequently, the flux leakage are minimized. Those familiar with the design problems peculiar to the inductor type of magneto's will appreciate the importanw of reducing the dimensions of the winding to a minimum, theproblem of finding edequate space for the stationary winding and for a distributor bearing of adequate-length Within the dimensions'permissible, being a difiicult one.

Again, in the construction illustrated, a material "reduction in weight is effected by reason of the reduced size, the attachment of pole pieces by casting to the unit frame structure, and by the-use of aluminum for the frame.

It is clear from the foregoing description that the parts ofmy improved generator can 'of opposite polarity, an L- keeping the tion of a stator comprising readily be assembled and disassembled and it need only be added that the generating coil and associated arts can be disassem-, bled without disturbing the rotor and its associated parts, a. feature which constitutes a marked difference from the prior generators. -It will be noted that while'the core (3). and the pole piece (4) must be made se-pae rate to permit the turning of the core to cylindrical form, it is not necessary for this purpose that the core be made integral with the pole piece (3). Indeed it is obvious that the upper pole structure can for this purpose be formed and arranged in relation'to each other in various ways without sacrificin the advantages incidentto 'theimachining 0% the pole pieces as a unitary art of the frame structure, the 'cylindrica ,turning of the core, and the disassembly of the coil Without A dismounting the rotor. And in general, it will be understood that the construction shown and described is resented for purposes of illustration an explanation and that my improvements in many respects can be embodied in difiierent constructions, the scope of the invention being indicated by the appended claims.

What I claim is:

1. In an ignition generator, the combination of a stator comprisin pole structures of opposite polarity, an L-s aped permanent magnet having en agement at its respective ends with the sai opposite pole structures on plane surfaces at right angles to each other, a magnetic rotor disposed between' the stator es, and a enerating windin in inductive relation to t 'e magnetic circuit throulgh the stator and rotor.

2. nan ignition generator, the-combination of a stator comprising ole structures l'iapecl perma-- nent magnet having engagement at vits respective ends with the said op osite. pole v structures on plane surfaces at rlght angles to each other, a enerating winding on one of the stator pofies, and an inductor rotor disposed between the stator poles.

3. In an'ignition generator, the combination of astator comprising polestructures of opposite polarity, one of said pole struc "tures having a main pole and a by-pass, a

pole, an

generating winding on said main L-shaped permanent magnet having engage: ment at its'respective ends with the said opposite pole structures on plane surfaces at right angles to each other, and an inductor rotor disposed 'between the stator poles 1 adapted to distribute the magnetic fluxIalternately ;throug'h'the saidymain pole'and the b pass. 'Y 4. 11 an ignition generator, the combina f pole structuresof opposite 'polarit one said 'poleflstructures having a. cyindriar'pole, a circular-a;

generating coil fitted to said cylindrical pole, an L-shaped permanent magnet having engagement at its respective ends with said opposite pole structures on plane surfaces at right angles to each other, and an inductor rotor disposed between the poles of opposite polarity.

5, In an ignition enerator, the combination of an integra lly cast non-magnetic frame structure, a magnetic pole piece of one; polarity embedded and secured in the bottom of said frame, a ma etic pole structure of the opposite polarity in the upper part of the frame, said pole; structure comprising a pair of pole pieces embedded and secured in said frame and a magnetic member detachably engaging said pole piece, a generating winding in inductive relation to one of sald pair of pole pieces, an L-shaped permanent ma net having one end engaging the bottom p0 apiece and its other end enaging said magnetic member, and a rotor disposed between the pole pieces of opposite polarity and adapted y its rotation to vary the fluxthrough the said winding.-

6. In an ignition enerator, the combination of an integra 1y cast non-magneticframe structure, a magnetic pole piece of one polarity embedded and secured in the bottom of the frame, a magnetic pole structure of the opposite polarity in the upper part of the frame, said pole "structure comprising a main pole piece having its bottom part embedded and secured in the frame and provided with a projecting core part adapted to receive a generating coil over its upper end and a second pole piece embeddedand secured in the frame and adapted to constitute a by-pass around the main pole piece, a generating winding on the said core partof the main pole piece, an L-shaped permanent magnet havlng one end joined to the bottom pole piece and its other end magnetically joined to the upper ends of said main pole piece and by-pass, and an inductor rotor mounted between the opposite pole pieces. 7. In an ignition generator, the combination. of an integrally cast non-magnetic frame structure, a magnetic pole piece of one polarity embedded and secured in the bottom of the frame, a magnetic pole structure of the opposite polarity in the upper part of the frame, said pole structure comprising a main pole piece having its bottom part embedded and secured in the said frame, and provided with a projecting core part adapted to receive a generating coil over its upper end and a second pole pieeeembedded and secured in the frame and adapted to constitute a by-pass around the main pole piece and a magnetic member detachably engaging said pole pieces, a generating coil on the said core part of the main pole piece, an L-shaped permanent magnet havin one end joined to the bottom pole piece an its other end joined to the said detachable magnetic member, and an inductor rotor mounted between the opposite pole pieces.

8. In an ignition generator, the combination of an integra ly cast non-magnetic frame structure, a magnetic pole piece of one polarity embedded and secured in the bottom of the frame, a magneticpole structure of the opposite polarity in the upper part of -the frame, said pole structure comprising a main-pole piece having its bottom part embedded and secured in the said frame and provided witha projecting cylindrical core part adapted to receive a round generating coil over its upper end and a second pole piece embeddedand secured in the frame and adapted to constitute a'by-pass around the main pole piece and a magnetic member,-

detachably engaging said two pole pieces,

a round generating coil on the said core part of the main pole piece, an L-shaped permanent magnet having one end joined to the bottom pole piece and its other end joined to the said detachable magnetic member, and an inductor rotor mounted betweenathe opposite'pole pieces.

In testimony whereof, Ighereunto affix-my signature. 7

CHARLES H. TOWER. 

